Digital signage uses LCD or other technology display panels to display advertisements (ads) that are purchased by advertisers. Such advertisements may be situated on vending machines or in public or private places for viewing by potential buyers. In some instances, the presence of a viewer triggers play-out of the ad, while in other cases the advertisements are played out on a schedule. Regardless, advertisers often wish to ascertain with certainty that the ad time purchased was in fact provided. Hence, they may require proof of play-out. Proof of play-out is difficult to verify because of all the issues involved. For example, log files of play-out by the digital signage player can be provided to the advertiser but the LCD screen may have been disconnected or turned off. Also, systems to monitor and record the functioning of the LCD screen's backlight and electrical pulses can be developed but there is no guarantee that the video cables are plugged in. Additionally, a malfunction of the display itself (e.g., as a result of heat induced blackout of an LCD panel in direct sunlight) could prevent the image from actually being viewable.